The invention relates to combination rail and highway vehicles; that is, vehicles which can operate both on the highways using rubber tires, and on the rails of railroad tracks using guide wheels to guide the vehicles on the rails. Vehicles of this general type are shown in commonly owned U.S. Pat. Nos. 3,738,285; 3,763,789 and 3,653,332. Such vehicles are provided at their front and rear ends with guide rails for riding along rails with the front and rear tires of such vehicles riding upon the rails to drive and brake the vehicles.
With medium sized vehicles, such as passenger automobiles, the front and rear tires may be adjusted inwardly slightly toward one another so as to come into contact with the rails of a standard railroad track. The rails of a track of standard gage are separated, center-to-center, by approximately 59.5 inches. However, the center-to-center distance between the front tires of larger vehicles, such as heavy trucks, may be, for example, on the order of 75.2 inches. From a practical standpoint, it is nearly impossible to adjust the front wheels of large, heavy trucks so as to match the rail-to-rail distance between the rails of a standard track. On the other hand, the tires of the truck must have good traction on the rails to provide motive power and braking. Further, in order to maintain good tire alignment for safe operation of a truck on the highway, it is desirable that the front suspension system of the truck be subjected to as little tampering as possible.
A combination rail and highway vehicle, with wideset front tires and with good traction to rails is greatly to be desired.